Is radio sometimes more potent than theatre? Listening to Mike Bartlett's Love Contract on Radio 4 last year, I was both gripped and chilled. Seeing the play staged, under a new title, in an upstairs room at the Royal Court with 30 other people, I still find it compelling. The difference is that questions of plausibility arise when the play is visibly enacted.

Bartlett is definitely on to some-thing: the increasing invasion by big companies into their employees' privacy. With deft precision, he shows a power-dressed female manager interviewing Emma, from sales, about her love life. At first, there is something comic about the firm's legalistic definition of what constitutes a "romantic or sexual relationship". This, however, turns to morbid prurience when the manager demands intimate details of Emma's affair with a colleague, Darren. Alarm bells ring when the relationship goes on too long. Emma's pregnancy leads to enforced severance from Darren and ruthless manipulation of every aspect of her existence.

Could it happen? Quite conceivably. Two years ago, this paper reported an American survey revealing that 31 of 80 firms asked staff to declare office love affairs. Bartlett pursues this idea with impeccable logic, showing how employees, anxious to keep their jobs, become complicit. People, he suggests, even start to monitor themselves, with Darren reporting that sex with Emma was "excellent" while she classifies it as merely "good".

Bartlett, in the manner of early absurdist plays by Havel or Ionesco, takes a plausible premise to a lethal conclusion; and this is where the difference between radio and theatre becomes crucial. Emma's ultimate act is a surrender to the firm, but what was an imaginative metaphor on air becomes an improbable device on stage.

It remains a timely and engrossing 50-minute play. Lyndsey Turner's production, staged in a white-walled rehearsal room, captures exactly the right air of sanitised desiccation. Julia Davis shrewdly plays the desk-bound manager not as an Orwellian ogre but as someone who believes she is acting for the best: challenged by Emma over attempts to turn her into a single-minded success-worshipper, Davis blandly replies, "What else is there?"

Anna Madeley is excellent as Emma, showing how truculent defiance of corporate intrusiveness gradually gives way to willing compliance - chilling proof that, as the recession bites, we will increasingly permit companies to own us, body and soul.